The Tropical Hardwood Tree Improvement and Regeneration Center (TropHTIRC) is a collaborative research, development and extension partnership. Established in 2010, TropHTIRC’s mission is to advance the science of tropical hardwood tree improvement, regeneration, and conservation genetics. Our goal is to develop and disseminate knowledge to foster sustainable tropical hardwood forestry, production of forest products, restoration, and maintenance of genetically diverse ecosystems. We work with a diversity of partners to increase knowledge and develop strategies for breeding, conservation, utilization, silviculture, and marketing of tropical hardwoods. Through application of classical selection, genomics, advanced propagation, seed and nursery production technologies, we are developing improved lines of native trees. Our current focus is on Hawaii’s premier timber tree, koa (Acacia koa), an endemic Hawaiian species of substantial cultural, economic, and ecological importance. Executive summary
Koa seed orchards for Hawaii reforestation
Recent land use changes have led to opportunities to reforest large areas of degraded land with koa and there is now a large demand for improved koa seeds and seedlings. To meet this demand, HTIRC members have been awarded a competitive grant from the Forest Service State & Private Forestry and are working together to establish seed orchards to produce an abundant supply of seeds for reforestation across a range of environmental conditions from high to low elevations.
Developing wilt resistant Acacia koa for Hawaii
by Nicklos Dudley and Tyler Jones, Hawaii Agriculture Research Center
Koa wilt disease, caused by the fungus Fusarium oxysporum f. sp. koae, causes mortality of koa in native forests and is a major impediment to reforestation with this species. The Hawaii Agriculture Research Center (HARC) conducted a disease survey on the four largest Hawaiian Islands and developed a collection of over 500 F. oxysporum isolates. HARC has screened over 150 of the isolates for virulence in koa, and selected the ten most virulent isolates to use for screening young koa seedlings for genetic-resistance to the fungus. HARC then collected koa seeds from native forests and koa plantings on Hawaii, Maui, Oahu, and Kauai. From these collections, HARC screened over 450 half-sib famlies (seeds from the open-pollinated same mother tree) in greenhouse seedling trials.